1. Field of the Invention
The present invention relates to a magneto-optical recording apparatus capable of overwriting, and more particularly, to a magneto-optical recording apparatus capable of driving a magnetic field generator and an optical pickup simultaneously to allow the magnetic field generator to be compact.
2. Description of the Prior Art
Referring to FIGS. 1 and 2, a conventional magneto-optical recording apparatus is shown in the drawings, the magneto-optical recording apparatus includes a spindle motor 1 for rotating a magneto-optical disc 2 mounted on a shaft thereof, a laser driving circuit 3 disposed under and outside of the magneto-optical disc 2, and an optical pickup 4 movably connected to the laser driving circuit 3 for heating the magneto-optical recording disc 2 through a laser diode driven by the laser driving circuit 3.
Also, a magnetic field generator 6 is disposed above the magneto-optical disc 2 and magnetizes the magneto-optical disc 2 through a hole formed at a cartridge 5. Hence, the optical pickup 4 may heat the magneto-optical disc 2 by an operation of the laser diode driven by the laser driving circuit 3.
That is, the optical pickup 4 converts a beam emitted from the laser diode into a parallel beam and then applies the parallel beam to the magneto-optical disc 2 via an objective lens 4a, so that the magneto-optical disc 2 is heated to a certain temperature, thereby decreasing its coercive force. Furthermore, the coercive force becomes zero at the Curie temperature.
When the magneto-optical disc 2 is magnetized by applying a vertical magnetic field from the magnetic field generator 6 to the portion of the magneto-optical disc 2 having the thus decreased coercive force, the temperature of the magneto-optical disc 2 falls gradually to cause its coercive force increase. Accordingly, the thus increased coercive force can not be affected by even an external magnetic field.
In this case, in order to record data at high speed, magnetic field inversion of the magnetic field generator 6 must be performed at high speed and playback of the recorded data can be accomplished by detecting the Kerr rotation angle changed according to the magnetization direction through the optical pickup 4.
However, the above-mentioned conventional magneto-optical recording apparatus has disadvantages as follows. Since the magnetic field generator 6 for generating a vertical magnetic field is fixedly disposed above the magneto-optical disc 2, the magnetic field generator 6 must be larger in size in order to apply the magnetic field to an overall track of the magneto-optical disc 2. For a cartridge type of magneto-optical disc, since a distance between the magneto-optical disc 2 and the magnetic field generator 6 is relatively longer, the number of turns or amount of current required must be increased in order to generate a sufficient magnetic field. Accordingly, it is difficult to perform a high-speed magnetic field inversion due to the increased inductance.